Bit-race.



W. P. JOHNSON. BIT BRAGE.

APPLICATION FILED APR. 22,1908.

Patented June 8, 1909.

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W. P. JOHNSON.

BIT BEACH. APPLIOATION I'I'LED APR. 22,1908.

Patented June 8, 19%. '2 mum's-sum 2.

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' 10, having a pressure receiving knob 11 at crank portion of the brace. The mutually WILLIAM P. JOHNSON, OF PLUMTREE, NORTH CAROLINA.

BIT-B RA CE Specification of Letters Patent.

Patented June 8, 1909.

Application filed April 22, 1908. Serial No. 428,653.

T '0 all whom it may concern:

Be it known that I, VVILLIAM P. J our: sox, a citizen of the United States, residing at Plumtree, in the county of Mitchell, State of North Carolina, have invented certain new 1 and useful Improvements in Bit-Braces; and 1 I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilled in the art to which it appert-ains to make and i use the same.

This invention relates t-o bit braces and it i has for itsobject to provide a simple and etlicient construction, wherein a bit may be quickly engaged and disengaged, and when engaged, will be held securely in place.

Other objects and advantages of the invention will be understood from the following description.

In the drawings forming a portion of this specification and in which like numerals of reference indicate similar parts in the several views, Figure 1 isan elevation showing the brace with thejaws in disengaging position, Fig.2 is a view similar to Fig. 1, showing the gripping portion only of the brace, the jaws being 1n their engaging position, and locked, Fig. 3 is a view similar to Fig. 2, the retaining pawl or link being ready to spring forwardly to release the jaws, the spring pawl being depressed, Fig. 4 is a section on line 4-4 of Fig. 2, Fig. 5 1s a section on line 5-5 of Fig. 1, Fig. 6 is an elevation on an enlarged scale, of one of the j aw )rovided levers of the brace, Fig. 7 is a longitudinal section 7 through one of the. levers and the locking pawl or link, the rack being in elevation.

Referring now to the drawings, there is illustrated a brace, including the usual bar its upper end, and including a crank portion provided with a grip 11. The lower end of the bar 10, which is usually provided with a type of screw operated chuck, is in the present instance provided with a laterally ofi'set gripping jaw 12 to which is pivoted a cooperative aw 13 from which extends one arm 14 of the curved operating lever, the opposite end of which is bifurcated as shown at 15 and straddles the lower member 16 of the adjacent or grippingfaces of the jaws 12 and 13 may be constructed in any desired way to afiord an efficient gripping action.

In order to hold the gripping jaws 1.2 and 13 at times in fixed gripping relation, :1 locking link 17 is provided, wlnch is of U-shape and is disposed to straddle the lever arm 14, and likewise the lower portion 18 of the bar 10, to which portion 18, the extremities of the link are pivoted as illustrated. The piy'oted extremities of the legs of the U-shaped-link 17 are extended at substan- ,,tially a right angle from the portions that straddle the lever arm 14, to the pivot 19 by which they are connected to the portion 18 of the bar. The bight portion of the link is provided with a thumb piece 20 which may be grasped to facilitate the movement of this bight portion along the face of the lever arm 14 in a direction away from the jaws. By reason ofthe angular extensions of the free ends of the legs of the link 17, it will be understood that rearward movement of the bight portion of the link will affect rapid movement of the free end of the lever arm 14, in the direction of the portion 18 of the bar of the brace. The portion 18 forms in effect a lever extension of the jaw 12 in exaetly the same manner as the portion 14 forms a lever extension of the jaw 13, all of which will be readily understood.

The curved outer edge of the lever arm 14 is normally in engagement with the bight portion of the link 17.

To hold the link 17 in its rearward or locking position, the rack 21 is provided, this rack having an integral spring extension 22 at one end, which extension is disposed against the inner face or edge ofthe lever arm 14, in which position this spring held rack bar is secured by a pin passed through the lever arm 14 and throughthe embracing ears 23 formed upon the spring extension of the rack. The spring extension 22 serves to hold the rack normally with its teeth pro jected beyond the outer or upper face of the lever arm 14 so that its teeth may receive the pawl lip 24 formed on the inner face of the bight of the lockin link. To facilitate depression of -the rac into releasing position, it is provided at its free end with a thumb extension 25.

Secured to: the inner edge portion of the member 18, is a leaf spring 26, the free end of which bears against the inner end of the lever arm 14, and serves to throw it outwardly and thus open the jaws, when the link 17 is thrown forwardly or in the direction of the jaws. In fact, as soon as the rack is depressed, the upward movement of the lever arm 14; under the influence of this leaf spring, serves to throw the link or pawl 17 into 1ts disengaging or forward position. Thus to release the bit, it is only necessary to press the thumb extension 25 of the spring Having thus described the invention what is claimed is:

1. clamp comprising gripping members, a locking member carried by one of the gripping members and movable into and out of position to hold the gripping mmebers in active correlation, said locking member including a knife-edge, and a rack yieldably supported on the second gripping member and movable into and out of position for engagement by the knife-edge.

2. A clamp comprising gripping members. a locking member carried by one of the gripping members and movable into and out of position to hold the ripping members in active correlation, said locking member including a knife-edge, a rack yieldably sup ported on the second gripping member and movable into and out of position for engagement by the knife-edge, and means for holding the rack normally and yieidably in engagement with the knife-edge,

' 3. A bit brace provided with a clamping jaw, a lever pivoted to said brace and having a clamping aw complementary to said brace jaw, a yielding rack bar carried by said lever, and a link pivotally secured to said brace and engaging the rack bar.

4. A bit brace provided with a clamping jaw, a lever pivoted to said bit brace and having a clamping jaw complementary to said bit brace jaw, a yielding rack bar carried by said lever, a link pivotally secured to said brace and engaging the rack bar, and

means to normally hold said rack bar in operative connection with said link.

In testimony whereof, I aiiix my signature, in presence of two witnesses.

\VILLIAM P. JOHNSON. VVitnes'ses S. L. BURLESON,

R. L. GARDEN. 

